Change wording of unclosed delimiter label

src/libsyntax/parse/lexer/tokentrees.rs

@@ -58,7 +58,10 @@ impl<'a> StringReader<'a> {
                         .next()  // these are in reverse order as they get inserted on close, but
                     {            // we want the last open/first close
                         if d == delim {
-                            err.span_label(*open_sp, "this might be the culprit...");
+                            err.span_label(
+                                *open_sp,
+                                "this delimiter might not be properly closed...",
+                            );
                             err.span_label(
                                 *close_sp,
                                 "...as it matches this but it has different indentation",

src/test/ui/issue-2354.rs

@@ -12,7 +12,7 @@
 
 fn foo() { //~ NOTE un-closed delimiter
   match Some(x) {
-  //~^ NOTE this might be the culprit...
+  //~^ NOTE this delimiter might not be properly closed...
       Some(y) => { panic!(); }
       None => { panic!(); }
 }

src/test/ui/issue-2354.stderr

@@ -4,7 +4,7 @@ error: this file contains an un-closed delimiter
 LL | fn foo() { //~ NOTE un-closed delimiter
    |          - un-closed delimiter
 LL |   match Some(x) {
-   |                 - this might be the culprit...
+   |                 - this delimiter might not be properly closed...
 ...
 LL | }
    | - ...as it matches this but it has different indentation

src/test/ui/parser-recovery-1.stderr

@@ -4,7 +4,7 @@ error: this file contains an un-closed delimiter
 LL | trait Foo {
    |           - un-closed delimiter
 LL |     fn bar() {
-   |              - this might be the culprit...
+   |              - this delimiter might not be properly closed...
 ...
 LL | }
    | - ...as it matches this but it has different indentation

src/test/ui/parser/unclosed-braces.rs

@@ -24,7 +24,7 @@ fn main() {
 //~^ NOTE un-closed delimiter
     {
         {
-        //~^ NOTE this might be the culprit...
+        //~^ NOTE this delimiter might not be properly closed...
             foo();
     }
     //~^ NOTE ...as it matches this but it has different indentation

src/test/ui/parser/unclosed-braces.stderr

@@ -5,7 +5,7 @@ LL | fn main() {
    |           - un-closed delimiter
 ...
 LL |         {
-   |         - this might be the culprit...
+   |         - this delimiter might not be properly closed...
 ...
 LL |     }
    |     - ...as it matches this but it has different indentation